Bad reactions to prescription drugs send 700,000 Americans to emergency rooms each year, according to a new federal study providing the most detailed look yet at the problem.
The report, appearing today in the Journal of the American Medical Assn., said allergic reactions were the most common adverse drug events causing ER visits, followed by unintentional overdoses.
(The study excluded suicide attempts.)
People older than 65 were more than twice as likely as younger people to require emergency care for a drug reaction, and nearly seven times as likely to need hospitalization.
Sixteen of the top 18 drugs causing adverse reactions have been in use for more than 20 years.
Researchers found that three medications the bloodthinner warfarin
Researchers found that three medications the bloodthinner warfarin, the diabetes drug insulin and the heart medicine digoxin — accounted for one-third of drug-related emergency room visits among people over 65.
Those drugs’ margin of safety is relatively narrow, researchers said.
Among all patients, insulin and warfarin led the list of drugs causing bad reactions, followed by amoxicillin, aspirin and trimethoprim-sulfamethoxazole, an antibiotic.
The report, by the Centers for Disease Control and Prevention, the Food and Drug Administration and the Consumer Product Safety Commission, included 63 hospitals’ figures from last year and 2004. It differed from previous research because it was national and because it identified which drugs were most troublesome.
Dr. Daniel Budnitz, a CDC epidemiologist and lead author of the study, said many of the drugs causing bad reactions were “good, life-saving drugs” but the findings showed that the medical community needed to do “a more careful job monitoring and working with patients.”
Budnitz said elderly patients were nearly as likely to receive emergency treatment for an adverse drug event as for a motor vehicle injury.
bad drug reactions accounted for 2.5% of emergency room visits for unintentional injuries
For the population as a whole, bad drug reactions accounted for 2.5% of emergency room visits for unintentional injuries and 6.7% of injuries leading to hospitalizations.
“I think it is a big problem,” said Dr. David Bates of Brigham and Women’s Hospital in Boston, who has done previous research on the subject.
“The absolute number of patients identified in the study is high.”
Bates said that many bad drug reactions were preventable and that more careful prescribing might lessen the problem. Prescribing slightly lower doses to elderly patients, who often have kidney problems and other health complications, might help prevent overdoses.
Dr. Thomas Scaletta, an emergency room physician at Edward Hospital in Naperville, Ill., and president of the American Academy of Emergency Medicine, said doctors were concerned that the problem would deepen as baby boomers reached retirement.